Coronary air embolism during removal of a central venous catheter

Background
Acute air embolism has been described during central venous cannulation, but it may also occur during catheter removal in a spontaneously breathing patient. We describe an episode of acute coronary ischaemia that occurred during CV catheter removal.

Case report
A 23-year-old male, multiple trauma patient was treated over 27 days in an ITU. He required a tracheostomy, two weeks of mechanical ventilation, and several surgical interventions. On the 27th day, he was scheduled to be transferred to a low-dependency area and his CVC was removed from the left subclavian vein. After five minutes, the pressure pad was released from the site of cannulation; the patient started coughing and became dyspnoeic. He developed tachyarrhythmia with ST depression in the 2nd, 3rd and aVF leads, followed by marked ST elevation, and subsequently, ventricular fibrillation. The patient was placed in the Trendelenburg position and CPR was started. Normal sinus rhythm returned after three defibrillations. Echocardiography revealed the presence of a large amount of air bubbles within the left ventricle, which disappeared spontaneously within one minute. The patient quickly regained consciousness and his condition returned to normal within 12 h, with transient elevation of heart enzymes. Five days later, he was decannulated and transferred to the orthopaedic ward in a satisfactory condition.

Discussion
Air embolism during CV catheter removal is a rare event, but it may occur when a persistent tunnel remains after prolonged cannulation, associated with negative intrathoracic pressure created by a spontaneously breathing or coughing patient. In the case described, acute myocardial ischaemia occurred in the region supplied by the right coronary artery, which is located higher than the left one and is therefore more exposed to air bubbles. We could not demonstrate, however, the presence of a persistent foramen ovale, however some connection had to exist between the right and left sides of the heart in our patient.

Conclusion
Special caution should be exercised during CV catheter removal, and the procedure should be always done with the patient placed in the Trendelenburg position.